/*******************************************************************************************
 * Copyright (c) 2006-2009 Alex Robson, Rob Simmons, Craig Israel, and Rachel Twyford
 *
 * Use of this software in any form requires that you have both 
 * read and agreed to the following terms:
 *
 * Permission is hereby granted, free of charge, to any person obtaining
 * a copy of this software and associated documentation files (the "Software"), 
 * to deal in the Software without restriction, including without limitation 
 * the rights to use, copy, modify, merge, publish, distribute, sublicense, 
 * and/or sell copies of the Software, and to permit persons to whom the
 * Software is furnished to do so, subject to the following conditions: 
 *
 * Redistributions of source code must retain the above copyright
 * notice, this list of conditions and the following disclaimer.
 * Redistributions in binary form must reproduce the above copyright notice, 
 * this list of conditions and the following disclaimer in the 
 * documentation and/or other materials provided with the distribution.
 * Neither the name of Nvigorate nor the names of its contributors may 
 * be used to endorse or promote products derived from this software without 
 * specific prior written permission. 
 *
 * THIS SOFTWARE IS PROVIDED "AS IS" AND ANY
 * EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
 * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE 
 * DISCLAIMED. IN NO EVENT SHALL ANY CONTRIBUTOR BE LIABLE FOR ANY
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 * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
 * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS 
 * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
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using System;
using System.Collections.Generic;
using System.Linq;
using Nvigorate.Data.Query;
using Nvigorate.Relational.Builders;
using Nvigorate.Relational.Mapping.Index;
using Nvigorate.Relational.Mapping.Interface;

namespace Nvigorate.Relational.Repository
{
    public abstract class PersistBuilder
    {
        protected IEnumerable<IAssignment> _assignments;
        protected ISourceMap _sourceMap;
        protected IPersistenceKeyManager _keyManager;
        protected Func<IAssignment, bool> _assignmentFilter;

        #region Metadata

        protected IEnumerable<IAssignment> Assignments
        {
            get
            {
                if (_assignments == null)
                {
                    _assignments = SourceMap
                        .Assignments
                        .Where(_assignmentFilter);
                }
                return _assignments;
            }
        }

        protected IPersistable Persistable { get; set; }

        protected IQueryObject InsertInstanceIntoKeyTable
        {
            get
            {
                return _keyManager.GetInsertIntoKeyTable(Persistable);
            }
        }

        protected Output OutputClause
        {
            get
            {
                return _keyManager.GetOutputClauseForSource(Persistable, SourceMap, "INSERTED");
            }
        }

        protected IPersistable Parent { get; set; }

        protected Type ParentType { get; set; }

        protected IRepositoryMapIndex RepositoryMapIndex { get; set; }

        protected ISourceMap SourceMap
        {
            get
            {
                return _sourceMap;
            }
        }

        protected Type TargetType
        { get; set; }

        #endregion

        public abstract IQueryObject Build(bool enforceConcurrency);

        public static PersistBuilder GetBuilderForInstance(ISourceMap sourceMap, IPersistenceKeyManager keyManager, IPersistable target, IPersistable parent)
        {
            if (!sourceMap.CanInsert && !sourceMap.CanUpdate)
                return new PersistNothingBuilder(sourceMap, keyManager, target, parent);

            if ((target.IsNew && sourceMap.CanInsert) || (target.IsDirty && !sourceMap.CanUpdate))
                return new InsertBuilder(sourceMap, keyManager, target, parent);

            return new UpdateBuilder(sourceMap, keyManager, target, parent);
        }

        public PersistBuilder(ISourceMap sourceMap, IPersistenceKeyManager keyManager, IPersistable target, IPersistable parent)
        {
            _sourceMap = sourceMap;
            Persistable = target;
            TargetType = target.InstanceType;
            Parent = parent;
            ParentType = parent == null ? typeof(object) : parent.GetType();
            _keyManager = keyManager;
        }
    }
}
